Do you realize how ridiculous a mention of "cytoskeletal microtubules" appears to anyone with the most rudimentary education in cell biology? Can you name an instance of non-cytoskeletal microtubules?

Here is one of many hits I found using the term "cytoskeletal microtubules" in a google search.

It was from The Journal of Cell Biology where they were distinguishing cytoskeletal microtubules from flagellar microtubules.

In that context it is a meaningful distinction. However, neurons lack flagella, cilia, and mitotic spindles (the last of which is still the cytoskeleton IMO).

Are you trying to claim that Penrose was distinguishing anything from flagellar, ciliary, or spindle microtubules, or was he just adding extra polysyllabic words to his tome?

IMO, it's just part of an attempt to obfuscate his sloppy equivocation between the cytoskeleton and the microtubule cytoskeleton.

Again, changes in the actin cytoskeleton have been implicated in neuronal plasticity to a far greater degree than the microtubule cytoskeleton (including the transport of mRNAs encoding beta-actin and actin-binding proteins), yet Penrose ignores it. It seems to me as though he heard about MTs first and can't be bothered with anything more holistic, even though emergent properties involving both are involved in a fibroblast moving 5 microns on a plastic dish.

If that can't be reduced, how sensible is it to believe that consciousness can be reduced so much further?